1. Field of the Invention
This invention relates to devices for rotating a polygonal fastener, such as a bolt head, nut or like. The new device has an open-end wrench structure with a movable jaw, ratchet control apparatus.
2. Description of Related Art
Fixed jaw, open-end wrenches known in the art may be limited in use for rotating polygonal fasteners because of a long swing or rotational movement requirement. For example, for a hexagonal headed bolt the wrench arm must be rotated 60 degrees to reposition the wrench on adjacent faces of the bolt head to continue to rotate the bolt. This may prevent use of the wrench in areas with limited space. Also, repositioning the wrench for each stroke may add time and effort to manipulating the fastener. Closed-ring configured wrenches allow smaller swing angles, but may still have to be repositioned, or if a socket-type ratchet, may not be used on hydraulic lines, fuel lines, fasteners with long shafts and the like due to vertical clearance requirements.
There may be various devices and inventions know that have been developed in attempts to produce a strong, compact open-end ratcheting wrench. The general approaches for such devices may include: a wrench with fixed jaws that have a special shape that applies torque in one direction and slips around the fastener in an opposite direction; a wrench with both jaws integral with the handle, having small pawls, rollers or camming components carried around their internal surfaces to allow gripping movement of a fastener in only one direction; and open-end wrenches with one or both jaws unidirectionally relieving to allow ratcheting. The first type of mechanism only allows large rotational or swing angle use, that is, for a hexagonal bolt head the swing angle would be 60 degrees. The second type of wrench may be inherently fragile and complicated to manufacture and assemble.
A third type of open-end ratcheting wrenches, those that use a relieving jaw, may have failed to achieve both adequate strength and a compact profile. Several designs may utilize a movable jaw that may be slideably positioned over a wrench head with an attached fixed jaw and may be fastened by a pin to allow rotation of the movable jaw. This may result in a weak mechanism with a bulky head. Another design that has a movable jaw slideably positioned over a wrench head or handle with curved surfaces for engagement when torqueing a fastener is also fastened by a pin positioned in a slot. This design appears to also result in a weak mechanism resulting in breakage of the jaw mechanism as experienced by users.
U.S. Pat. No. 7,886,631 discloses an open-end ratcheting wrench that includes a first wrench member having a cavity and a second wrench member with a ratcheting element positioned within the cavity. An insert is positioned between a forward face of the ratcheting element and a forward portion of the first wrench member. The invention disclosed herein represents an improvement over the wrench disclosed therein in that it provides a more durable structure. In order to accommodate the cavity insert, it was necessary to form a depression in the front portion of the ratcheting member which greatly weakened the area. By positioning the cavity insert between a rearward wall of the cavity and a bearing surface on the rear portion of the ratcheting member, the depression is no longer required and thus the ratcheting element is significantly strengthened. The cavity insert functions as a retaining member for the ratcheting element, provides a bearing surface for the ratcheting element and includes a spring seat for the elastic element.